Radiocarbon dating is commonly used to date

Progressively through time, the carbon-14 atoms decay and once again become nitrogen-14.

As a result, there is a changing ratio of carbon-14 to the more atomically stable carbon-12 involves actually counting individual carbon-14 atoms.

This allows the dating of much older and smaller samples but at a far higher cost.

Sample sizes of one gram or greater are required for conventional dates.

More recently, accelerator mass spectrometry (AMS) has become widely available.

Carbon dating (aka radiocarbon dating) is pretty reliable, when the samples are good, up to 30 or 40 thousand years ago, and in some cases the method can be extended to just over 100 thousand years ago.

Developed by a chemist born in Colorado, there are now commercial and academic laboratories across the globe that conduct radiocarbon dating.

Radiocarbon dating is used to determine the age of fossils, or of historical artificacts that are made with some organic content such as wood, cotton, bone, etc.

It gives an accurate date, but only up to a certain age.

The first dated materials included wood from Egyptian tombs, linen wrapping from one of the Dead Sea Scrolls, and heartwood from a California sequoia.

Radiocarbon dating is useful for dating organic materials as old as 45,000 to 50,000 years, after which little C atoms in a sample decay.

Radiometric dating is also used to date archaeological materials, including ancient artifacts.